Ratioless near-threshold level translator

ABSTRACT

An output circuit, between a first power supply terminal and a second power supply terminal, receives a first logic signal that switches between a first logic state based on a voltage at the first power supply terminal and a second logic state based on a voltage at the second power supply terminal and provides a second logic signal, complementary to the first logic signal. A level translator is in a second power supply domain configured to have a second voltage differential between a third power supply terminal and a fourth power supply terminal, wherein the second voltage differential is greater than the first voltage differential. The level translator is designed so that it may be implemented using a subset of the transistors that have the shortest channel length and narrowest channel width.

BACKGROUND

1. Field

This disclosure relates generally to level translators, and morespecifically, to ratioless, near-threshold level translators.

2. Related Art

Level translators take advantage of different techniques to managecontentious internal nodes, particularly at levels near the thresholdsof the constituent transistors. As electronic device continue to growsmaller, new techniques are required to manage these contentious nodeswhile also managing size, energy use, and other design issues.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is illustrated by way of example and is notlimited by the accompanying figures, in which like references indicatesimilar elements. Elements in the figures are illustrated for simplicityand clarity and have not necessarily been drawn to scale.

FIG. 1 illustrates a high-level block diagram of an example leveltranslation system, in accordance with certain embodiments of thepresent disclosure;

FIG. 2 illustrates an example lower voltage translator, in accordancewith certain embodiments of the present disclosure;

FIG. 3 illustrates an example upper voltage translator, in accordancewith certain embodiments of the present disclosure; and

FIG. 4 illustrates an example dual voltage translator, in accordancewith certain embodiments of the present disclosure.

DETAILED DESCRIPTION

Level translators may be used in a variety of configurations, systemimplementations, etc. One particular system implementation may involvetranslating signals from one level to another in a range near thethresholds of the translator's constituent transistors. For example, alevel translator may be used to translate a source-biased input to anunbiased source on a different voltage domain.

Depending on the configuration, it may also be necessary and/ordesirable to be able to translate levels for one or more aspects of agiven input. For example, a level translator may be operable totranslate two different voltage levels (e.g., a top rail voltage and abottom rail voltage) associated with the same input. Depending on theconfiguration, however, the level translator may be operable totranslate only one aspect, and/or only one aspect at any one time.

In order to manage contentious internal nodes (i.e., those nodes atwhich a plurality of components attempt to provide different electricaloutcomes at the same node), level translators have implemented varioustechniques. One such technique is the use of transistors of differingsizes in order to ensure that the appropriate outcome is achieved. Thistechnique may be referred to as implementing a particular “ratio” withrespect to certain transistors. However, the use of larger transistorsmay have difficulties scaling when the manufacturing process scales.Further, designing such ratios may make it more difficult to account forvariability among individual transistors. Still further, repeatedoperation of circuits implementing transistors of different sizes may,over time, result in changes to the individual transistors, thusaltering the actual ratios and reducing performance.

One area in which these concerns may be of particular note is at aninterface between logic domains in which the number of incoming signalsis large, with each signal using a separate (or substantially separate)level translator. For example, in an interface between a digitalprocessing block and an analog flash memory block, there may be aboutfour hundred individual signal lines. An interface may be implementedsuch that each line uses a separate level translator. With such a largenumber of level translators, managing performance while accounting forvariations in individual transistors and size considerations increasesin difficulty.

FIG. 1 illustrates a high-level block diagram of an example leveltranslation system 100, in accordance with certain embodiments of thepresent disclosure. System 100 may include level translator 102electrically coupled to both input logic domain 104 and output logicaldomain 106. Level translator 102 may be any appropriate circuit, asdescribed in more detail below with reference to FIGS. 2-4, operable totranslate a chosen electrical properties (e.g., current, voltage, etc.)of input logic domain 104 to a corresponding electrical aspect of outputlogical domain 106. For example, level translator 102 may be operable totranslate one or more voltage levels associated with input logic domain104 to one or more different voltage levels associated with outputlogical domain 106.

In some embodiments, input logic domain 104 may be any appropriatesystem, device, circuit, logic, interface, or other combination ofelectrical components operable to provide a plurality of input signals(e.g., IN₁ and IN₂) to level translator 102, as described in more detailbelow with reference to FIGS. 2-4. For example, input logic domain 104may be digital circuitry implementing some digital logic, responsive toan input signal (e.g., V_(IN)). This may include, for example, some orall of a processing array associated with a system on chip. In such anexample, input logic domain 104 may operate with two voltage levels,each associated with a logic level. For example, V_(DD1) may beassociated with a logical “high” and V_(SS1) may be associated with alogical “low.” In some embodiments, the voltage levels associated withthe logical levels of input logic domain 104 may vary depending on oneor more operating modes of input logic domain 104. For example, thehigher voltage may vary from 1-1.4 V, while the lower voltage may varyfrom 0-0.4 V.

In some embodiments, output logical domain 106 may be any appropriatesystem, device, circuit, logic, interface, or other combination ofelectrical components operable to receive a plurality of output signals(e.g., OUT₁ and OUT₂) from level translator 102, as described in moredetail below with reference to FIGS. 2-4. For example, output logicaldomain 104 may be logic circuitry with an output signal (e.g., V_(OUT)).This may include, for example, an output driver for driving an inputsignal for a flash memory array. Output logic domain 106 may also haveassociated a plurality of logic levels, with a voltage associated witheach logic level. For example, V_(DD2) may be associated with a logical“high” and V_(SS2) may be associated with a logical “low.”

System 100 may be operable to translate one or more electricalproperties (e.g., voltage) from one logical domain to another (e.g.,from input logic domain 104 to output logical domain 106) so long as thedifference between those properties is within an operational range ofratioless level translator 102. For example, level translator 102 mayoperate to translate V_(DD1) to V_(DD2) so long as the differencebetween V_(DD1) and V_(DD2) is less than the threshold voltage of theindividual transistors comprising level translator 102.

In some embodiments, the electrical properties (e.g., voltage)associated with the same logic levels of different logic domains may bethe same, substantially the same, or different. In the same oralternative embodiments, the property associated with one logic levelmight be the same (or substantially the same) while the propertyassociated with another logic level might be different. For example,level translator 102 may be operable to translate only the voltagelevels associated with a logical “high,” only the voltage levelsassociated with a logical “low,” and/or both voltage levels in parallel.

As described in more detail below with reference to FIGS. 2-4, system100 may be configured such that these translations may be made usingminimum-size transistors within level translator 102.

FIG. 2 illustrates an example lower voltage translator 200, inaccordance with certain embodiments of the present disclosure.Translator 200 may be electrically coupled to input circuitry 202 andoutput circuitry 216, and operable to translate a first lower voltageassociated with input circuitry 202 (e.g., V_(SS1)) into a second lowervoltage associated with output circuitry 216 (e.g., V_(SS2)). Althoughtwo upper voltages are shown (e.g., V_(DD1) and V_(DD2)) for thepurposes of translator 200, they may be considered equal. In someembodiments, input circuitry 202 may generally correspond to a portionof input logic domain 104, while output circuitry 216 may generallycorrespond to a portion of output logic domain 106.

In some embodiments, input circuitry 202 may be an inverting circuitproviding two input signals (e.g., IN₁ and IN₂) to a level translator.These signals may be logical inverses of one another. In the illustratedexample, input circuitry 202 may include an n-type transistorelectrically coupled to a p-type transistor.

In some embodiments, translator 200 may include a plurality of n-typeand p-type transistors. For ease of description, these transistors maybe referred to as “NFETs” and “PFETs,” respectively, although one ofordinary skill in the art may note that other appropriate types oftransistors may be used without departing from the scope of the presentdisclosure. For example, translator 200 may include a plurality of passtransistors 208, 214 electrically coupled to a plurality of outputtransistors 204, 206, and electrically coupled to a plurality of keeptransistors 210, 212. Although certain names have been provided indescription of the various components of translator 200 in order to aidillustration, other (or no) names may be applied without departing fromthe scope of the present disclosure.

Throughout this disclosure, transistors may be described as having oneor more current electrodes rather than specifically designating one suchelectrode according to the particular type of transistor involved. Forexample, a transistor may be described as having a “first currentelectrode” and a “second current electrode.” Further, transistors may bedescribed as having a “control electrode” rather than using anyterminology specific to a particular type of transistor. For example,the gate of a MOSFET may be referred to as a “control electrode.”Further, throughout this disclosure, connections between various partsof transistors may be referred to as being “coupled” and/or“electrically coupled” to one another. These terms may be usedinterchangeably.

In some embodiments, translator 200 may include a plurality of outputtransistors. For example, translator 200 may include transistors 204,206. Transistors 204, 206 may be operable to provide a first outputsignal (e.g., OUT₁) dependent upon a second input signal (e.g., IN₂, theinverse of a first input signal IN₁). Transistors 204, 206 may beoperable to provide a logical “high” to the first output signal (andthus the associated second higher voltage source V_(DD2)) when the firstinput signal (e.g., IN₁) is high, and a logical “low” to the firstoutput signal (and thus the associated second lower voltage sourceV_(SS2)) when the first input signal is low.

In some configurations, transistor 204 may be an NFET, while transistor206 may be a PFET. Transistors 204, 206, may be coupled to one anotherat one of their respective current electrodes. The other currentelectrodes may be coupled to different voltage sources. For example,transistor 204 may have its other current electrode coupled to a secondlower voltage source (e.g., V_(SS2)), while transistor 206 may have itsother current electrode coupled to a second higher voltage source (e.g.,V_(DD2)). The control electrode of transistor 206 may be coupled to aninput signal (e.g., IN₂), while the control electrode of transistor 204may be alternatively coupled to either the same input signal (e.g., IN₂)or a first lower source voltage (e.g., V_(SS1)), depending on the stateof the second output signal (e.g., OUT₂), as described in more detailbelow. For example, the control electrode of transistor 204 may becoupled to a current electrode of both transistors 208, 214, as well asa current electrode of transistor 212 at the node labeled as “C₁.”

In some embodiments, translator 200 may include a plurality of passtransistors. For example, translator 200 may include transistors 208,214. In some configurations, transistor 214 may be an NFET, whiletransistor 208 may be a PFET. Transistors 208, 214 may each have a firstcurrent electrode coupled to one another, as well as a second currentelectrode coupled to one another. One set of current electrode coupledto one another may occur at the node labeled as “C₁.” Transistor 208 mayhave a control electrode coupled to a first low voltage source (e.g.,V_(SS1)), while transistor 214 may have a control electrode coupled to asecond output signal (e.g., OUT₂), as described in more detail below).

In some embodiments, translator 200 may also include a plurality of keeptransistors. For example, translator 200 may include transistors 210,212, which may both be NFETs. Transistors 210 may have one currentelectrode coupled to one current electrode of transistor 212, while theother current electrode may be coupled to a second lower voltage source(e.g., V_(SS2)). The control electrode of transistor 210 may be coupledto a first output signal (e.g., OUT₁). The other current electrode oftransistor 212 may be coupled to transistors 204, 206, 208, 214, whilethe control electrode of transistor 212 may be coupled to a first inputsignal (e.g., IN₁). Transistor 210 may be operable to manage leakagecurrent through transistor 204 in certain logical states of the inputsignal. Transistor 212 may be operable to manage contention over thevoltage level at node C₁, as described in more detail below.

In prior level translators, contention has arisen at certain nodesduring transition from one logical state to another logical state. Thatis, during transition, different transistors attempted to change avoltage level at a node in competing ways. For example, prior leveltranslators may have only included one keep transistor, the controlelectrode of which may have been coupled to a first output voltage. Onecurrent electrode may have been coupled to a lower voltage source. Theother current electrode may have been coupled to a control electrode ofa lower output transistor and a control electrode of a pass transistorat a certain node that may be referred to here as a “first contentionnode.” In such a configuration, however, the pass and keep transistorsmay have competed to change the voltage at the first contention nodewhen the first input signal transitioned from a “high” value to a “low”value. One technique to attempt to manage this contention has been tohave a pass transistor substantially larger than the keep transistor.However, for a variety of size, cost, performance, and/or processreasons, including transistors of differing sizes may be undesirable.

Another technique to manage this contention has been to include adecoupling transistor coupled to the keep transistor. For example, thekeep transistor may have had a current electrode coupled to a currentelectrode of the decoupling transistor rather than to the firstcontention node. The decoupling transistor may have had its othercurrent electrode coupled to the first contention node, and its controlelectrode coupled to a first input signal. However, such a configurationmay have still resulted in a leakage path during certain logical statesof the input signal. Further, an additional contention point may havedeveloped at a second contention node—the node at which the outputtransistors are coupled to one another. In this situation. When thefirst input signal transitioned from a “low” value to a “high” value,the output transistors may have competed to change the voltage at thesecond contention node. Again, one technique to address this contentionmay be to make an upper output transistor substantially larger than abottom output transistor. Again, however, transistors of different sizesmay be undesirable.

Referring again to FIG. 2, translator 200 may also include transistor214. As described in more detail above, transistor 214 may be controlledby a second output signal (e.g., OUT₂), which may be the logical inverseof the first output signal (e.g., OUT₁). Transistor 214 may be operableto manage the contention associated with a transition from a “low” to a“high” at node C₂. In addition, the use of the second output signal inthe control of transistor 214 may be operable to manage a leakage pathassociated with transistor 214.

In some embodiments, the second output signal (e.g., OUT₂) may beprovided by output circuitry 216. For example, output circuitry 216 maybe an inverting circuit operable to logically invert the first inputsignal (e.g., OUT₁) provided by the level translation circuitry. In someembodiments, output circuitry 216 may be an integral part of leveltranslator 102. In the same or alternative embodiments, output circuitry216 may be part of second logic domain 106. For example, outputcircuitry 216 may be an inverter that may be one of a plurality ofinverters and/or additional circuitry implementing an output buffer.

In operation, translator 200 may translate a first lower voltage level(e.g., V_(SS1)) to a second lower voltage level (e.g., V_(SS2)) (e.g., a“bottom rail translator”). Further, translator 200 may be implementedusing transistors such that all transistors of a given type (e.g., alln-type transistors, all p-type transistors) are of substantially thesame size. Moreover, all transistors in translator 200 may be of aminimum size as required by the manufacturing process. That is, the sizeof the transistors may be driven primarily by the design requirements ofthe manufacturing process rather than the design requirements of thecircuit performance. Further, this minimum size may be scalable with themanufacturing process such that, as the transistors get smaller, so doesthe overall size of translator 200. Thus, even by adding transistors totranslator 200, the overall size of translator 200 may be greatlyreduced due to the elimination of larger transistors.

In the same or alternative embodiments, system 100 may also includetranslator 300 (e.g., a top rail translator), as described in moredetail below with reference to FIG. 3. Depending on designconfigurations, translator 200 and translator 300 may be parts of thesame circuit, parts of different circuits, located on the samesemiconductor device, and/or located on different semiconductor devices.System 100 may include translators 200, 300 in the same implementationof translator 102, different implementations of translator 102, and/orin multiple implementations of translator 102.

FIG. 3 illustrates an example upper voltage translator 300, inaccordance with certain embodiments of the present disclosure.Translator 300 may be electrically coupled to input circuitry 302 andoutput circuitry 316, and operable to translate a first upper voltageassociated with input circuitry 302 (e.g., V_(DD1)) into a second uppervoltage associated with output circuitry 316 (e.g., V_(DD2)). Althoughtwo lower voltages are shown (e.g., V_(SS1) and V_(SS2)), for thepurposes of translator 300, they may be considered equal. In someembodiments, input circuitry 302 may generally correspond to a portionof input logic domain 104, while output circuitry 316 may generallycorrespond to a portion of output logic domain 106.

In some embodiments, input circuitry 302 may be an inverting circuitproviding two input signals (e.g., IN₁ and IN₂) to a level translator.These signals may be logical inverses of one another. In the illustratedexample, input circuitry 302 may include an n-type transistorelectrically coupled to a p-type transistor.

In some embodiments, translator 300 may include a plurality of n-typeand p-type transistors. For ease of description, these transistors maybe referred to as “NFETs” and “PFETs,” respectively, although one ofordinary skill in the art may note that other appropriate types oftransistors may be used without departing from the scope of the presentdisclosure. For example, translator 300 may include a plurality of passtransistors 308, 314 electrically coupled to a plurality of outputtransistors 304, 306, and electrically coupled to a plurality of keeptransistors 310, 312. Although certain names have been provided indescription of the various components of translator 300 in order to aidillustration, other (or no) names may be applied without departing fromthe scope of the present disclosure.

In some embodiments, translator 300 may operate in an invertedcomplimentary manner to translator 200 such that translator 300 mayoperate to translate a first upper voltage associated with inputcircuitry 302 to a second upper voltage associated with input circuitry316. Translator 300 may include transistors 304, 306 coupled to oneanother at one of their respective current electrodes. The other currentelectrodes may be coupled to different voltage sources. In someconfigurations, transistor 304 may be an NFET, while transistor 306 maybe a PFET. For example, transistor 304 may have its other currentelectrode coupled to a second lower voltage source (e.g., V_(SS2)),while transistor 306 may have its other current electrode coupled to asecond higher voltage source (e.g., V_(DD2)). The control electrode oftransistor 304 may be coupled to an input signal (e.g., IN₂), while thecontrol electrode of transistor 306 may be alternatively coupled toeither the same input signal (e.g., IN₂) or a first upper source voltage(e.g., V_(DD1))) depending on the state of the second output signal(e.g., OUT₂), as described in more detail below. For example, thecontrol electrode of transistor 306 may be coupled to a currentelectrode of both of transistors 308, 314, as well as a currentelectrode of transistor 312 at the node labeled as “C₁.”

In some embodiments, translator 300 may include a plurality of passtransistors. For example, translator 300 may include transistors 308,314. In some configurations, transistor 308 may be an NFET, whiletransistor 314 may be a PFET. Transistors 308, 314 may each have a firstcurrent electrode coupled to one another, as well as a second currentelectrode coupled to one another. One set of current electrode coupledto one another may occur at the node labeled as “C₁.” Transistor 308 mayhave a control electrode coupled to a first upper voltage source (e.g.,V_(DD1)) while transistor 314 may have a control electrode coupled to asecond output signal (e.g., OUT₂), as described in more detail below).

In some embodiments, translator 300 may also include a plurality of keeptransistors. For example, translator 300 may include transistors 310,312, which may both be PFETs. Transistor 310 may have one currentelectrode coupled to one current electrode of transistor 312, while theother current electrode may be coupled to a second upper voltage source(e.g., V_(DD2)). The control electrode of transistor 310 may be coupledto a first output signal (e.g., OUT₁). The other current electrode oftransistor 312 may be coupled to transistors 304, 306, 308, 314, whilethe control electrode of transistor 312 may be coupled to a first inputsignal (e.g., IN₁). Transistor 310 may be operable to manage leakagecurrent through transistor 304 in certain logical states of the inputsignal. Transistor 312 may be operable to manage contention over thevoltage level at node C₁.

In some embodiments, translator 300 may also include transistor 314. Asdescribed in more detail above, transistor 314 may be controlled by asecond output signal (e.g., OUT₂), which may be the logical inverse ofthe first output signal (e.g., OUT₁). Transistor 314 may be operable tomanage the contention associated with a transition from a “low” to a“high” at node C₂. In addition, the use of the second output signal inthe control of transistor 314 may be operable to manage a leakage pathassociated with transistor 314.

In some embodiments, the second output signal (e.g., OUT₂) may beprovided by output circuitry 316. For example, output circuitry 316 maybe an inverting circuit operable to logically invert the first inputsignal (e.g., OUT₁) provided by the level translation circuitry. In someembodiments, output circuitry 316 may be an integral part of leveltranslator 102. In the same or alternative embodiments, output circuitry316 may be part of second logic domain 106. For example, outputcircuitry 316 may be an inverter that may be one of a plurality ofinverters and/or additional circuitry implementing an output buffer.

In operation, translator 300 may translate a first upper voltage level(e.g., V_(DD1)) to a second upper voltage level (e.g., V_(DD2)) (e.g., a“top rail translator”). Further, translator 300 may be implemented usingtransistors such that all transistors of a given type (e.g., all n-typetransistors, all p-type transistors) are of substantially the same size.Moreover, all transistors in translator 300 may be of a minimum size asrequired by the manufacturing process. That is, the size of thetransistors may be driven primarily by the design requirements of themanufacturing process rather than the design requirements of the circuitperformance. Further, this minimum size may be scalable with themanufacturing process such that, as the transistors get smaller, so doesthe overall size of translator 300. Thus, even by adding transistors totranslator 300, the overall size of translator 300 may be greatlyreduced due to the elimination of larger transistors.

In the same or alternative embodiments, system 100 may also includetranslator 400 (e.g., a dual rail translator), as described in moredetail below with reference to FIG. 4. Depending on designconfigurations, translators 200, 300, 400 may be parts of the samecircuit, parts of different circuits, located on the same semiconductordevice, and/or located on different semiconductor devices. System 100may include translators 200, 300, 400 in the same implementation oftranslator 102, different implementations of translator 102, and/or inmultiple implementations of translator 102.

FIG. 4 illustrates an example dual voltage translator 400, in accordancewith certain embodiments of the present disclosure. Translator 400 maybe electrically coupled to input circuitry 402 and output circuitry 424,and operable to translate a first lower voltage and a first uppervoltage associated with input circuitry 402 (e.g., V_(SS1) and V_(DD1))into a second lower voltage and a second upper voltage associated withoutput circuitry 424, respectively (e.g., V_(SS2) and V_(DD2)). In someembodiments, input circuitry 402 may generally correspond to a portionof input logic domain 104, while output circuitry 424 may generallycorrespond to a portion of output logic domain 106.

In some embodiments, input circuitry 402 may be an inverting circuitproviding two input signals (e.g., IN₁ and IN₂) to a level translator.These signals may be logical inverses of one another. In the illustratedexample, input circuitry 402 may include an n-type transistorelectrically coupled to a p-type transistor.

In some embodiments, translator 400 may include a plurality of n-typeand p-type transistors. For example, translator 400 may include aplurality of pass transistors 408, 414, 416, 422 electrically coupled toa plurality of output transistors 404, 406, and electrically coupled toa plurality of keep transistors 410, 412, 418, 420. Although certainnames have been provided in description of the various components oftranslator 400 in order to aid illustration, other (or no) names may beapplied without departing from the scope of the present disclosure.

In some embodiments, translator 400 may include a plurality of outputtransistors. For example, translator 400 may include transistors 404,406. Transistors 404, 406 may be operable to provide a first outputsignal (e.g., OUT₁) dependent upon a second input signal (e.g., IN₂, theinverse of a first input signal IN₁). Transistors 404, 406 may beoperable to provide a logical “high” to the first output signal (andthus the associated second higher voltage source V_(DD2)) when the firstinput signal (e.g., IN₁) is high, and a logical “low” to the firstoutput signal (and thus the associated second lower voltage sourceV_(SS2)) when the first input signal is low.

In some configurations, transistor 404 may be an NFET, while transistor406 may be a PFET. Transistors 404, 406, may be coupled to one anotherat one of their respective current electrodes. The other currentelectrodes may be coupled to different voltage sources. For example,transistor 404 may have its other current electrode coupled to a secondlower voltage source (e.g., V_(SS2)), while transistor 406 may have itsother current electrode coupled to a second higher voltage source (e.g.,V_(DD2)). The control electrode of transistor 406 may be coupled to acurrent electrode of both of transistors 416, 422, as well as a currentelectrode of transistor 420 at the node labeled as “C₁.” The controlelectrode of transistor 404 may be coupled to a current electrode ofboth of transistors 408, 414, as well as a current electrode oftransistor 412 at the node labeled as “C₃.”

In some embodiments, translator 400 may include a plurality of passtransistors. For example, translator 400 may include transistors 408,414, 416, 422. In some configurations, transistors 414, 416 may beNFETs, while transistors 408, 422 may be PFETs. Transistors 416, 422 mayeach have a first current electrode coupled to one another, as well as asecond current electrode coupled to one another. One set of currentelectrodes coupled to one another may occur at the node labeled as “C₁.”Transistor 416 may have a control electrode coupled to a first uppervoltage source (e.g., V_(DD1)), while transistor 422 may have a controlelectrode coupled to a second output signal (e.g., OUT₂). Transistors408, 414 may each have a first current electrode coupled to one another,as well as a second current electrode coupled to one another. One set ofcurrent electrode coupled to one another may occur at the node labeledas “C₃.” Transistor 408 may have a control electrode coupled to a firstlow voltage source (e.g., V_(SS1)), while transistor 414 may have acontrol electrode coupled to a second output signal (e.g., OUT₂).

In some embodiments, translator 400 may also include a plurality of keeptransistors. For example, translator 400 may include transistors 410,412, which may both be NFETs, as well as transistors 418, 420, which mayboth be PFETs. Transistor 410 may have one current electrode coupled toone current electrode of transistor 412, while the other currentelectrode may be coupled to a second lower voltage source (e.g.,V_(SS2)). The control electrode of transistor 410 may be coupled to afirst output signal (e.g., OUT₁). The other current electrode oftransistor 412 may be coupled to transistors 404, 408, 414, while thecontrol electrode of transistor 412 may be coupled to a first inputsignal (e.g., IN₁). Transistor 410 may be operable to manage leakagecurrent through transistor 404 in certain logical states of the inputsignal. Transistor 412 may be operable to manage contention over thevoltage level at node C₃.

In the same or alternative embodiments, transistor 418 may have onecurrent electrode coupled to one current electrode of transistor 420,while the other current electrode may be coupled to a second uppervoltage source (e.g., V_(DD2)). The control electrode of transistor 418may be coupled to a first output signal (E.g., OUT₁). The other currentelectrode of transistor 420 may be coupled to transistor 406, 416, 422,while the control electrode of transistor 420 may be coupled to a firstinput signal (e.g., IN₁). Transistor 418 may be operable to manageleakage current through transistor 406 in certain logical states of theinput signal. Transistor 420 may be operable to manage contention overthe voltage level at node C₁.

Translator 400 may also include transistors 414, 422. As described inmore detail above, transistors 414, 422 may be controlled by a secondoutput signal (e.g., OUT₂), which may be the logical inverse of thefirst output signal (e.g., OUT₁). Transistors 414, 422 may be operableto manage the contention associated with a transition from a “low” to a“high” at node C₂. In addition, the use of the second output signal inthe control of transistors 414, 422 may be operable to manage a leakagepath associated with transistors 414, 422.

In some embodiments, the second output signal (e.g., OUT₂) may beprovided by output circuitry 424. For example, output circuitry 424 maybe an inverting circuit operable to logically invert the first inputsignal (e.g., OUT₁) provided by the level translation circuitry. In someembodiments, output circuitry 424 may be an integral part of leveltranslator 102. In the same or alternative embodiments, output circuitry424 may be part of second logic domain 106. For example, outputcircuitry 424 may be an inverter that may be one of a plurality ofinverters and/or additional circuitry implementing an output buffer.

In operation, translator 400 may translate both a first lower voltagelevel (e.g., V_(SS1)) to a second lower voltage level (e.g., V_(SS2))and a first upper voltage level (e.g., V_(DD1)) to a second uppervoltage level (e.g., V_(DD2)) (e.g., a “dual rail translator”). Further,translator 400 may be implemented using transistors such that alltransistors of a given type (e.g., all n-type transistors, all p-typetransistors) are of substantially the same size. Moreover, alltransistors in translator 400 may be of a minimum size as required bythe manufacturing process. That is, the size of the transistors may bedriven primarily by the design requirements of the manufacturing processrather than the design requirements of the circuit performance. Further,this minimum size may be scalable with the manufacturing process suchthat, as the transistors get smaller, so does the overall size oftranslator 400. Thus, even by adding transistors to translator 400, theoverall size of translator 400 may be greatly reduced due to theelimination of larger transistors.

By now it should be appreciated that there has been provided aratioless, near-threshold level translator that may be implemented totranslate one or more levels using transistors of the same orsubstantially the same size, allowing for a greater degree ofscalability of the level translation circuitry.

The level translator may include circuitry including an output circuit(202, 302) coupled between a first power supply terminal and a secondpower supply terminal that receives (IN₁) a first logic signal thatswitches between a first logic state based on a voltage at the firstpower supply terminal (V_(DD1)) and a second logic state based on avoltage at the second power supply terminal (V_(SS1)) and provides asecond logic signal (IN₂), complementary to the first logic signal, thatswitches between a first logic state based on a voltage at the firstpower supply terminal and a second logic state based on a voltage at thesecond power supply terminal. The circuitry may also include a leveltranslator that includes a first transistor (214, 314) of a first typehaving a first current electrode for receiving the first logic signal, asecond current electrode, and a control electrode; a first transistor(208, 308) of a second type having a first current electrode forreceiving the first logic signal, a second current electrode coupled tothe second current electrode of the first transistor of the first type,and a control electrode coupled to the second power supply terminal; asecond transistor (206, 304) of the second conductivity type having acontrol electrode that receives the first input signal, a first currentelectrode coupled to a third power supply terminal (V_(DD2), V_(SS2)),and a second current electrode as a first output; a second transistor(212, 312) of the first conductivity type having a first currentelectrode coupled to the second current electrode of the firsttransistor of the second conductivity type, a control electrode forreceiving the first logic signal, and a second current electrode; athird transistor (210, 310) of the first conductivity type having afirst current electrode coupled to the second current electrode of thesecond transistor of the first conductivity type, a second currentelectrode coupled to a fourth power supply terminal (V_(SS2), V_(DD2));and a control electrode coupled to the second current electrode of thesecond transistor of the second conductivity type; a fourth transistor(204, 306) of the first conductivity type having a control electrodecoupled to the second current electrode of the first transistor of thesecond conductivity type, a first current electrode coupled to thesecond current electrode of the second transistor of the secondconductivity type, and a second current electrode coupled to the fourthpower supply terminal; and an inverting circuit (216, 316) coupled tothe third and fourth power supply terminals having an input coupled tothe second current electrode of the second transistor of the secondconductivity type and an output coupled to the control electrode of thefirst transistor of the first conductivity type.

In some embodiments, this circuit may be implemented such that thefirst, second, third, and fourth transistors of the first conductivitytype have the same channel length and channel width. The first andsecond transistors of the second conductivity type may also have thesame channel length and channel width.

In the same or alternative embodiments, this circuit may be implementedsuch that the circuit has a minimum channel length and minimum channelwidth for transistors and the first, second, third, and fourthtransistors of the first conductivity type have the minimum channellength and channel width. The first and second transistors of the secondconductivity type may also have the minimum channel length and channelwidth.

In some embodiments, the first conductivity type may be N channel andthe second conductivity type may be P channel. In such a configuration,the first and third power supply terminals may be configured to receivea first voltage at a first level, the second power supply terminal maybe configured to receive a second voltage that is negative with respectto the first voltage, and the fourth power supply terminal may beconfigured to receive a third voltage that is more negative than thesecond voltage with respect to the first voltage.

In the same or alternative embodiments, the second conductivity type maybe N channel and the first conductivity type may be P channel. In such aconfiguration, the first and third power supply terminals may beconfigured to receive a first voltage at a first level, the second powersupply terminal may be configured to receive a second voltage that ispositive with respect to the first voltage, and the fourth power supplyterminal may be configured to receive a third voltage that is morepositive than the second voltage with respect to the first voltage.

In some embodiments, the level translator may further include a fifthtransistor (416) of the first conductivity type having a first currentelectrode that receives the second logic signal, a control electrodecoupled to the first power supply terminal, and a second currentelectrode coupled to the control electrode of the second transistor ofthe second conductivity type; a third transistor (422) of the secondconductivity type having a first current electrode that receives thesecond logic signal, a control electrode coupled to the output of theinverting circuit, and a second current electrode coupled to the controlelectrode of the second transistor of the second conductivity type; afourth transistor (420) of the second conductivity type having a firstcurrent electrode coupled to the second current electrode of the thirdtransistor of the second conductivity type, a control electrode thatreceives the second logic signal, and a second current electrode; and afifth transistor (418) of the first conductivity type having a firstcurrent electrode coupled to the second current electrode of the fourthtransistor of the second conductivity type, a second current electrodecoupled to the third power supply terminal (V_(DD2)); and a controlelectrode coupled to the second current electrode of the secondtransistor of the second conductivity type.

The circuit described above may be implemented such that the first,second, third, fourth, and fifth transistors may be of the firstconductivity type and the first, second, third, fourth, and fifthtransistors may be of the second conductivity type have the same channellength and channel width. Further, the first, second, third, fourth, andfifth transistors may be of the first conductivity type and the first,second, third, fourth, and fifth transistors may be of the secondconductivity type have the same channel length and channel width.

In some embodiments, the first conductivity type may be N channel, thesecond conductivity type may be P channel, the first power supplyterminal may be configured to receive a first voltage at a first level,the second power supply terminal may be configured to receive a secondvoltage that is negative with respect to the first voltage, the thirdpower supply terminal may be configured to receive a third voltage thatis positive relative to the first voltage, and the fourth power supplyterminal may be configured to receive a fourth voltage that is negativerelative to the second voltage.

In the same or alternative embodiments, the first conductivity type maybe P channel, the second conductivity type may be N channel, the firstpower supply terminal may be configured to receive a first voltage at afirst level, the second power supply terminal may be configured toreceive a second voltage that is positive with respect to the firstvoltage, the third power supply terminal may be configured to receive athird voltage that is negative relative to the first voltage, and thefourth power supply terminal may be configured to receive a fourthvoltage that is positive relative to the second voltage.

In some embodiments, the inverting circuit (424) may include a sixthtransistor of the first conductivity type having a first currentelectrode coupled to the fourth power supply terminal, a controlelectrode coupled to the second current electrode of the fourthtransistor of the first conductivity type, and a second currentelectrode coupled to the control electrode of the first transistor ofthe first conductivity type; and a sixth transistor of the secondconductivity type having a first current electrode coupled to the thirdpower supply terminal, a control electrode coupled to the second currentelectrode of the fourth transistor of the first conductivity type, and asecond current electrode coupled to the control electrode of the thirdtransistor of the second conductivity type.

In some embodiments, the circuitry may include an output circuit (202,302) in a first power supply domain configured to have a first voltagedifferential between a first power supply terminal and a second powersupply terminal, wherein the output circuit receives a first logicsignal (IN₁) that switches between a first logic state based on avoltage at the first power supply terminal (V_(DD1)) and a second logicstate based on a voltage at the second power supply terminal (V_(SS1))and provides a second logic signal (IN₂), complementary to the firstlogic signal, that switches between a first logic state based on avoltage at the first power supply terminal and a second logic statebased on a voltage at the second power supply terminal; and a leveltranslator in a second power supply domain configured to have a secondvoltage differential between a third power supply terminal and a fourthpower supply terminal, wherein the second voltage differential isgreater than the first voltage differential.

The level translator may include a first transistor (214, 314) of afirst type having a first current electrode for receiving the firstlogic signal, a second current electrode, and a control electrode; afirst transistor (208, 308) of a second type having a first currentelectrode for receiving the first logic signal, a second currentelectrode coupled to the second current electrode of the firsttransistor of the first type, and a control electrode coupled to thesecond power supply terminal; a second transistor (206, 304) of thesecond conductivity type having a gate that receives the first inputsignal, a source coupled to a third power supply terminal (V_(DD2),V_(SS2)) and a drain as a first output terminal of the level translator;a second transistor (212, 312) of the first conductivity type having adrain coupled to the second current electrode of the first transistor ofthe second conductivity type, a gate configured to receive the firstlogic signal, and a source; a third transistor (210, 310) of the firstconductivity type having a drain coupled to the source of the secondtransistor of the first conductivity type, a source coupled to a fourthpower supply terminal (V_(SS2)) V_(DD2)); and a gate coupled to thefirst output terminal; a fourth transistor (204, 306) of the firstconductivity type having a gate coupled to the second current electrodeof the first transistor of the second conductivity type, a drain coupledto the first output terminal, and a source coupled to the fourth powersupply terminal; and an inverting circuit (216, 316) coupled to thethird and fourth power supply terminals having an input coupled to thefirst output terminal and an output coupled to the control electrode ofthe first transistor of the first conductivity type.

In such circuitry, the first, second, third, and fourth transistors ofthe first conductivity type may have the same channel length and channelwidth. Further, the circuit may have a minimum channel length andminimum channel width for transistors and the first, second, third, andfourth transistors of the first conductivity type may have the minimumchannel length and channel width.

In such circuitry, the level translator may further include a fifthtransistor (416) of the first conductivity type having a first currentelectrode that receives the second logic signal, a control electrodecoupled to the first power supply terminal, and a second currentelectrode coupled to the gate of the second transistor of the secondconductivity type; a third transistor (422) of the second conductivitytype having a first current electrode that receives the second logicsignal, a control electrode coupled to the output of the invertingcircuit, and a second current electrode coupled to the gate of thesecond transistor of the second conductivity type; a fourth transistor(420) of the second conductivity type having a drain coupled to thesecond current electrode of the third transistor of the secondconductivity type, a gate configured to receive the second logic signal,and a source; and a fifth transistor (418) of the second conductivitytype having a drain coupled to the source of the fourth transistor ofthe second conductivity type, a source coupled to the third power supplyterminal (V_(DD2)); and a gate coupled to the first output.

In some embodiments, circuitry may be designed using transistors,wherein a subset of the transistors have the shortest channel length andnarrowest channel width. The circuitry may include an output circuit(202, 302) in a first power supply domain configured to have a firstvoltage differential between a first power supply terminal and a secondpower supply terminal, wherein the output circuit receives a first logicsignal (IN₁) that switches between a first logic state based on avoltage at the first power supply terminal (V_(DD1)) and a second logicstate based on a voltage at the second power supply terminal (V_(SS1))and provides a second logic signal (IN₂), complementary to the firstlogic signal, that switches between a first logic state based on avoltage at the first power supply terminal and a second logic statebased on a voltage at the second power supply terminal; and a leveltranslator having in a second power supply domain configured to have asecond voltage differential between a third power supply terminal and afourth power supply terminal, wherein the second voltage differential isgreater than the first voltage differential.

The level translator may include from the subset, a first transistor(214, 314) of a first type having a first current electrode forreceiving the first logic signal, a second current electrode, and acontrol electrode; from the subset, a first transistor (208, 308) of asecond type having a first current electrode for receiving the firstlogic signal, a second current electrode coupled to the second currentelectrode of the first transistor of the first type, and a controlelectrode coupled to the second power supply terminal; from the subset,a second transistor (206, 304) of the second conductivity type having agate that receives the first input signal, a source coupled to a thirdpower supply terminal (V_(DD2), V_(SS2)), and a drain as a first outputterminal of the level translator; from the subset, a second transistor(212, 312) of the first conductivity type having a drain coupled to thesecond current electrode of the first transistor of the secondconductivity type, a gate configured to receive the first logic signal,and a source; from the subset, a third transistor (210, 310) of thefirst conductivity type having a drain coupled to the source of thesecond transistor of the first conductivity type, a source coupled to afourth power supply terminal (V_(SS2), V_(DD2)); and a gate coupled tothe first output terminal; from the subset, a fourth transistor (204,306) of the first conductivity type having a gate coupled to the secondcurrent electrode of the first transistor of the second conductivitytype, a drain coupled to the first output terminal, and a source coupledto the fourth power supply terminal; and an inverting circuit (216, 316)coupled to the third and fourth power supply terminals having an inputcoupled to the first output terminal and an output coupled to thecontrol electrode of the first transistor of the first conductivitytype, wherein the inverting circuit comprises transistors from thesubset.

Because the apparatus implementing the present invention is, for themost part, composed of electronic components and circuits known to thoseskilled in the art, circuit details will not be explained in any greaterextent than that considered necessary as illustrated above, for theunderstanding and appreciation of the underlying concepts of the presentinvention and in order not to obfuscate or distract from the teachingsof the present invention.

What is claimed is:
 1. A circuit, comprising: an output circuit (202,302, 402) coupled between a first power supply terminal and a secondpower supply terminal that receives (IN1) a first logic signal thatswitches between a first logic state based on a voltage at the firstpower supply terminal (VDD1) and a second logic state based on a voltageat the second power supply terminal (VSS1) and provides a second logicsignal (IN2), complementary to the first logic signal, that switchesbetween a first logic state based on a voltage at the first power supplyterminal and a second logic state based on a voltage at the second powersupply terminal; and a level translator, comprising: a first transistor(214, 314, 416) of a first conductivity type having a first currentelectrode for receiving the first logic signal, a second currentelectrode, and a control electrode; a first transistor (208, 308, 422)of a second type having a first current electrode for receiving thefirst logic signal, a second current electrode coupled to the secondcurrent electrode of the first transistor of the first type, and acontrol electrode coupled to the second power supply terminal; a secondtransistor (206, 304, 406) of the second conductivity type having acontrol electrode that receives the first input signal, a first currentelectrode coupled to a third power supply terminal (VDD2, VSS2), and asecond current electrode as a first output; a second transistor (212,312, 412) of the first conductivity type having a control electrode forreceiving the first logic signal; a third transistor (210, 310, 410) ofthe first conductivity type having a control electrode coupled to thesecond current electrode of the second transistor of the secondconductivity type, wherein first and second current electrodes of thesecond and third transistors of the first conductivity type are coupledin series between a fourth power supply terminal and the second currentelectrode of the first transistor of the second conductivity type; afourth transistor (204, 306, 404) of the first conductivity type havinga control electrode coupled to the second current electrode of the firsttransistor of the second conductivity type, a first current electrodecoupled to the second current electrode of the second transistor of thesecond conductivity type, and a second current electrode coupled to thefourth power supply terminal; and an inverting circuit (216, 316, 416)coupled to the third and fourth power supply terminals having an inputcoupled to the second current electrode of the second transistor of thesecond conductivity type and an output coupled to the control electrodeof the first transistor of the first conductivity type.
 2. The circuitof claim 1, wherein the first, second, third, and fourth transistors ofthe first conductivity type have the same channel length and channelwidth.
 3. The circuit of claim 2, wherein the first and secondtransistors of the second conductivity type have the same channel lengthand channel width.
 4. The circuit of claim 1, wherein the circuit has aminimum channel length and minimum channel width for transistors and thefirst, second, third, and fourth transistors of the first conductivitytype have the minimum channel length and channel width.
 5. The circuitof claim 4, wherein the first and second transistors of the secondconductivity type have the minimum channel length and channel width. 6.The circuit of claim 1, wherein the first conductivity type is N channeland the second conductivity type is P channel.
 7. The circuit of claim6, wherein the first and third power supply terminals are configured toreceive a first voltage at a first level, the second power supplyterminal is configured to receive a second voltage that is negative withrespect to the first voltage, and the fourth power supply terminal isconfigured to receive a third voltage that is more negative than thesecond voltage with respect to the first voltage.
 8. The circuit ofclaim 1, wherein the second conductivity type is N channel and the firstconductivity type is P channel.
 9. The circuit of claim 8, wherein thefirst and third power supply terminals are configured to receive a firstvoltage at a first level, the second power supply terminal is configuredto receive a second voltage that is positive with respect to the firstvoltage, and the fourth power supply terminal is configured to receive athird voltage that is more positive than the second voltage with respectto the first voltage.
 10. The circuit of claim 1, wherein the leveltranslator further comprises; a fifth transistor (416) of the firstconductivity type, interposed between the control electrode of thesecond transistor of the second conductivity type and the second logicsignal, having a first current electrode that receives the second logicsignal (IN2), a control electrode coupled to the first power supplyterminal (VDD1), and a second current electrode coupled to the controlelectrode of the second transistor of the second conductivity type; athird transistor (422) of the second conductivity type, interposedbetween the control electrode of the second transistor of the secondconductivity type and the second logic signal, having a first currentelectrode that receives the second logic signal, a control electrodecoupled to the output of the inverting circuit, and a second currentelectrode coupled to the control electrode of the second transistor ofthe second conductivity type; a fourth transistor (420) of the secondconductivity type having a control electrode that receives the firstlogic signal; and a fifth transistor (418) of the second conductivitytype having a control electrode coupled to the second current electrodeof the second transistor of the second conductivity type, wherein firstand second current electrodes of the fourth and fifth transistors of thesecond conductivity type are coupled in series between the third powersupply terminal and the second current electrode of the third transistorof the second conductivity type.
 11. The circuit of claim 10, wherein:the first, second, third, fourth, and fifth transistors of the firstconductivity type and the first, second, third, fourth, and fifthtransistors of the second conductivity type have the same channel lengthand channel width.
 12. The circuit of claim 10, wherein: the first,second, third, fourth, and fifth transistors of the first conductivitytype and the first, second, third, fourth, and fifth transistors of thesecond conductivity type have the same channel length and channel width.13. The circuit of claim 10, wherein the first conductivity type is Nchannel, the second conductivity type is P channel, the first powersupply terminal is configured to receive a first voltage at a firstlevel, the second power supply terminal is configured to receive asecond voltage that is negative with respect to the first voltage, thethird power supply terminal is configured to receive a third voltagethat is positive relative to the first voltage, and the fourth powersupply terminal is configured to receive a fourth voltage that isnegative relative to the second voltage.
 14. The circuit of claim 10,wherein the first conductivity type is P channel, the secondconductivity type is N channel, the first power supply terminal isconfigured to receive a first voltage at a first level, the second powersupply terminal is configured to receive a second voltage that ispositive with respect to the first voltage, the third power supplyterminal is configured to receive a third voltage that is negativerelative to the first voltage, and the fourth power supply terminal isconfigured to receive a fourth voltage that is positive relative to thesecond voltage.
 15. The circuit of claim 10, wherein the invertingcircuit comprises: a sixth transistor of the first conductivity typehaving a first current electrode coupled to the fourth power supplyterminal, a control electrode coupled to the second current electrode ofthe fourth transistor of the first conductivity type, and a secondcurrent electrode coupled to the control electrode of the firsttransistor of the first conductivity type; and a sixth transistor of thesecond conductivity type having a first current electrode coupled to thethird power supply terminal, a control electrode coupled to the secondcurrent electrode of the fourth transistor of the first conductivitytype, and a second current electrode coupled to the control electrode ofthe third transistor of the second conductivity type.
 16. A circuit,comprising: an output circuit (202, 302) in a first power supply domainconfigured to have a first voltage differential between a first powersupply terminal and a second power supply terminal, wherein the outputcircuit receives a first logic signal (IN1) that switches between afirst logic state based on a voltage at the first power supply terminal(VDD1) and a second logic state based on a voltage at the second powersupply terminal (VSS1) and provides a second logic signal (IN2),complementary to the first logic signal, that switches between a firstlogic state based on a voltage at the first power supply terminal and asecond logic state based on a voltage at the second power supplyterminal; and a level translator in a second power supply domainconfigured to have a second voltage differential between a third powersupply terminal and a fourth power supply terminal, wherein the secondvoltage differential is greater than the first voltage differential,comprising: a first transistor (214, 314) of a first type having a firstcurrent electrode for receiving the first logic signal, a second currentelectrode, and a control electrode; a first transistor (208, 308) of asecond type having a first current electrode for receiving the firstlogic signal, a second current electrode coupled to the second currentelectrode of the first transistor of the first type, and a controlelectrode coupled to the second power supply terminal; a secondtransistor (206, 304) of the second conductivity type having a gate thatreceives the first input signal, a source coupled to a third powersupply terminal (VDD2, VSS2), and a drain as a first output terminal ofthe level translator; a second transistor (212, 312) of the firstconductivity type having a drain coupled to the second current electrodeof the first transistor of the second conductivity type, a gateconfigured to receive the first logic signal, and a source; a thirdtransistor (210, 310) of the first conductivity type having a draincoupled to the source of the second transistor of the first conductivitytype, a source coupled to a fourth power supply terminal (VSS2, VDD2);and a gate coupled to the first output terminal; a fourth transistor(204, 306) of the first conductivity type having a gate coupled to thesecond current electrode of the first transistor of the secondconductivity type, a drain coupled to the first output terminal, and asource coupled to the fourth power supply terminal; and an invertingcircuit (216, 316) coupled to the third and fourth power supplyterminals having an input coupled to the first output terminal and anoutput coupled to the control electrode of the first transistor of thefirst conductivity type.
 17. The circuit of claim 16, wherein the first,second, third, and fourth transistors of the first conductivity typehave the same channel length and channel width.
 18. The circuit of claim16, wherein the circuit has a minimum channel length and minimum channelwidth for transistors and the first, second, third, and fourthtransistors of the first conductivity type have the minimum channellength and channel width.
 19. The circuit of claim 16, wherein the leveltranslator further comprises; a fifth transistor (416) of the firstconductivity type having a first current electrode that receives thesecond logic signal, a control electrode coupled to the first powersupply terminal, and a second current electrode coupled to the gate ofthe second transistor of the second conductivity type; a thirdtransistor (422) of the second conductivity type having a first currentelectrode that receives the second logic signal, a control electrodecoupled to the output of the inverting circuit, and a second currentelectrode coupled to the gate of the second transistor of the secondconductivity type; a fourth transistor (420) of the second conductivitytype having a drain coupled to the second current electrode of the thirdtransistor of the second conductivity type, a gate configured to receivethe second logic signal, and a source; and a fifth transistor (418) ofthe second conductivity type having a drain coupled to the source of thefourth transistor of the second conductivity type, a source coupled tothe third power supply terminal (VDD2); and a gate coupled to the firstoutput.
 20. A circuit designed using transistors, wherein a subset ofthe transistors have the shortest channel length and narrowest channelwidth, comprising: an output circuit (202, 302) in a first power supplydomain configured to have a first voltage differential between a firstpower supply terminal and a second power supply terminal, wherein theoutput circuit receives a first logic signal (IN1) that switches betweena first logic state based on a voltage at the first power supplyterminal (VDD1) and a second logic state based on a voltage at thesecond power supply terminal (VSS1) and provides a second logic signal(IN2), complementary to the first logic signal, that switches between afirst logic state based on a voltage at the first power supply terminaland a second logic state based on a voltage at the second power supplyterminal; and a level translator having in a second power supply domainconfigured to have a second voltage differential between a third powersupply terminal and a fourth power supply terminal, wherein the secondvoltage differential is greater than the first voltage differential,comprising: from the subset, a first transistor (214, 314) of a firsttype having a first current electrode for receiving the first logicsignal, a second current electrode, and a control electrode; from thesubset, a first transistor (208, 308) of a second type having a firstcurrent electrode for receiving the first logic signal, a second currentelectrode coupled to the second current electrode of the firsttransistor of the first type, and a control electrode coupled to thesecond power supply terminal; from the subset, a second transistor (206,304) of the second conductivity type having a gate that receives thefirst input signal, a source coupled to a third power supply terminal(VDD2, VSS2), and a drain as a first output terminal of the leveltranslator; from the subset, a second transistor (212, 312) of the firstconductivity type having a drain coupled to the second current electrodeof the first transistor of the second conductivity type, a gateconfigured to receive the first logic signal, and a source; from thesubset, a third transistor (210, 310) of the first conductivity typehaving a drain coupled to the source of the second transistor of thefirst conductivity type, a source coupled to a fourth power supplyterminal (VSS2, VDD2); and a gate coupled to the first output terminal;from the subset, a fourth transistor (204, 306) of the firstconductivity type having a gate coupled to the second current electrodeof the first transistor of the second conductivity type, a drain coupledto the first output terminal, and a source coupled to the fourth powersupply terminal; and an inverting circuit (216, 316) coupled to thethird and fourth power supply terminals having an input coupled to thefirst output terminal and an output coupled to the control electrode ofthe first transistor of the first conductivity type, wherein theinverting circuit comprises transistors from the subset.